Inferior Alveolar Canal Research Articles

Sexual dimorphism of inferior alveolar canal location: A record- based CBCT Study in Eastern India.

Background:Sex determination from unidentified skeletal remains a daunting task in forensic odontology. The mandible is the strongest and most durable of bones available for post-mortem profiling and its morphometric characteristics have been investigated. Less explored is the location of the mandibular canal which in a few populations has shown gender dimorphism.Aim:The present cross-sectional study explores sexual dimorphism in an eastern Indian population of Odisha from an analysis of cone-beam CT system (CBCT) images for the relative position of the mandibular canal and its foramina.Method and Materials:A total of 120 CBCT images from either gender (1:1 ratio) of adult dentate individuals aged 18–60 years were analysed for the relative position of the mandibular canal. Ten measurements (8- coronal and 2- from axial slices) concerning the mandibular canal; at the level of the mandibular foramen, mandibular first molar and mental foramen were performed. Unpaired Student's t-test was employed to compare variables between the sexes at P < 0.05 level of significance.Results:The results revealed statistically significant differences (P < 0.05) between the genders in most of the variables (8/10), with higher mean values in males compared to females except in the distance between mandibular foramen and anterior border of the ramus (2.648 ± 0.67 mm in females, 2.527 ± 0.75 mm in males) and in the distance between the canal and lingual cortical plate in the region of the first molar (14.515 ± 1.33 mm in females, 14.288 ± 2.01 mm in males).Conclusion:The relative position of the mandibular canal and its associated foramina show sexual dimorphism in an adult eastern Indian population.

Evaluating the risk factors of inferior alveolar nerve injury following removal of the mandibular third molars

Objective: To evaluate the risk factors of inferior alveolar nerve injury (IANI) after surgical removal of the mandibular third molars (M3) and present a new risk scoring system to predict the probability of IANI. Methods: Patients who underwent extraction of M3 in the Stomatology Hospital, Zhejiang University School of Medicine from April 2017 to December 2019 were involved. The investigators enrolled a sample composed of 949 mandibular third molars. Prediction model was used for univariate and multivariate analysis of gender, age, M3, inferior alveolar canal (IAC), and the contact between M3 and IAC, to assess the risk factors of IANI. Combined with the risk factors determined by the outcomes of prediction model, the risk scoring system was constructed. The diagnostic performance of each cut-off score was examined to conduct a risk stratification of IANI risk scores. The predictive ability and reliability of the model were evaluated. Results: In prediction model, twenty nine cases (4.4%, 29/664) experienced postoperative IANI. Number of root (P<0.01), depth of impaction (P<0.05), contact between M3 and IAC (P<0.01) and their contact position (P<0.05) were statistically significant as contributing risk factors of IANI. Specifically, the incidence of temporary IANI was higher in those who aged under 25 years (P<0.001), while female suffer more permanent injury (P<0.05). Based on the IANI risk scoring system, patients were stratified into low-risk, middle-risk and high-risk groups at cutoff scores of 3 and 4. The area under the receiver operator characteristic curve of the risk scoring system were 0.81 [95%CI (0.70-0.90), P=0.002] and 0.80 [95%CI (0.68-0.92), P=0.007] towards good discrimination. Conclusions: Age, gender, number of root, depth of impaction, and contact between M3 and IAC were risk factors of IANI. IANI risk scoring system might help in preoperative assessment, recognition of high-risk cases and decision-making to reduce IANI.

Validation of different protocols of inferior alveolar canal tracing using cone beam computed tomography (CBCT).

The objective of this study was to evaluate, compare and validate different protocols of inferior alveolar canal tracing. 60 DICOM files with a total of 80 inferior alveolar canals were retrieved and imported to a third-party software where all proposed protocols can be performed. Initially, inferior alveolar canal was traced by two oral and maxillofacial radiologists together on cone beam CT cross-sectional images and considered as the baseline for future comparisons. Oral and maxillofacial surgeon performed the proposed different protocols. The protocols were color-coded differently by the surgeon before being compared with the baseline canal by the radiologists through a 5-point scale. Results showed that no single protocol was successful in all cases, even the cross-sectional protocol. According to the present study, the hybrid protocol was the most accurate while the automatic protocol was the least accurate. The hybrid protocol was reliable and showed the highest number of successful applications followed by the commonly used cross-sectional protocol. Dental practitioners should be aware of the application of multiple protocols and their pros and cons as no single protocol was successful in all the cases. Applying the same protocols on a larger sample size using different cone beam CT and multislice CT machines with different exposure parameters is recommended.

RADIOLOGICAL PREDICTION OF INFERIOR ALVEOLAR NERVE INJURY FOLLOWING SURGICAL REMOVAL OF IMPACTED MANDIBULAR THIRD MOLAR- A COMPARATIVE STUDY BETWEEN PANORAMIC RADIOGRAPH AND CONE BEAM COMPUTED TOMOGRAPH

The chances of neurological complications following surgical removal of impacted mandibular third molar increase when there is close contact between the inferior alveolar nerve and the tooth root. Thus, it is important to evaluate the topographic relationship between them preoperatively. AIMS AND OBJECTIVES- To assess the possible nerve injury following extraction of impacted mandibular third molar by comparing the relevant panoramic features with cone beam computed tomography (CBCT) ndings and evaluate the diagnostic accuracy of OPG. MATERIAL AND METHODS –A total number of 30 patients requiring surgical removal of impacted mandibular third molar under local anesthesia and having a close relationship between impacted mandibular third molar and inferior alveolar canal in panoramic radiograph were included in the study and were advised for CBCT evaluation. Statistically signicant association w RESULTS - as found between darkening of the root in OPG and absence of narrowing of the canal in CBCT with P value 0.008 (P&lt;0.05) while distribution of darkening of the root (OPG) according to presence or absence of corticalisation (CBCT) was not statistically signicant . The panorami CONCLUSION - c radiographs may be useful to assess the close relationship between mandibular canal and third molar root tip but it cannot appraise the type of intimate relationship present between them for which CBCT is the reliable tool.

The Effectiveness of Semi-Automated and Fully Automatic Segmentation for Inferior Alveolar Canal Localization on CBCT Scans: A Systematic Review.

This systematic review aims to identify the available semi-automatic and fully automatic algorithms for inferior alveolar canal localization as well as to present their diagnostic accuracy. Articles related to inferior alveolar nerve/canal localization using methods based on artificial intelligence (semi-automated and fully automated) were collected electronically from five different databases (PubMed, Medline, Web of Science, Cochrane, and Scopus). Two independent reviewers screened the titles and abstracts of the collected data, stored in EndnoteX7, against the inclusion criteria. Afterward, the included articles have been critically appraised to assess the quality of the studies using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Seven studies were included following the deduplication and screening against exclusion criteria of the 990 initially collected articles. In total, 1288 human cone-beam computed tomography (CBCT) scans were investigated for inferior alveolar canal localization using different algorithms and compared to the results obtained from manual tracing executed by experts in the field. The reported values for diagnostic accuracy of the used algorithms were extracted. A wide range of testing measures was implemented in the analyzed studies, while some of the expected indexes were still missing in the results. Future studies should consider the new artificial intelligence guidelines to ensure proper methodology, reporting, results, and validation.

Compression of the Inferior Alveolar Canal by Mandibular Third Molar among Images Taken from Patients Visiting Dental Imaging Centres of Kathmandu: A Descriptive Cross-sectional Study.

Third molars are common teeth to be impacted. The position of mandibular third molar is such that it is in close contact with inferior alveolar canal which may lead to nerve damage during its removal. So, this study was conducted to find out the prevalence of compression of inferior alveolar canal by mandibular third molars. This descriptive cross-sectional study was conducted on images collected from Dental Imaging Centers of Nepal from 25th June 2020 to 15th February 2021 after obtaining ethical clearance from Nepal Health Research Council (Reference number: 2100). A convenience sampling method was used to collect 433 cone-beam computed tomography images showing the relation between the third molars and inferior alveolar canal. Data were analyzed using the Statistical Package for the Social Sciences version 16. Point estimate at 95% confidence interval was calculated along with frequency and proportion for the binary data. Out of 433 images, 135 (31.17%) (26.80-35.53 at 95% Confidence Interval) images showed compression of inferior alveolar nerve by mandibular third molar. The study result indicated that 16 (11.85%) buccally placed, 50 (37.03%) lingually placed and 69 (51.11%) inferiorly placed inferior alveolar canal were compressed by apices of mandibular third molars. The prevalence of compression of inferior alveolar canal by mandibular third molar was found to be similar to other studies done in similar settings. Compression of the canal was more evident when inferior alveolar canal is situated lingually.

Assessment of the relationship of the distance between mandibular first and second molars with the inferior alveolar canal and cortical bone plate in an Egyptian subpopulation: a CBCT study.

The aim of the current cone beam computed tomography (CBCT) study was to evaluate the proximity of mandibular first and second molar roots to the inferior alveolar canal (IAC) and mandibular cortex in an Egyptian subpopulation. Scans of 120 patients (480 molars, 960 roots) were obtained from the College of Dentistry database at the Suez Canal University, Egypt. Buccal and lingual bone plates and root thickness were measured at the specified resected root end 3 mm from the radiographic apex, and so was the proximity of the root apices to the IAC. Measurements of the right and left mandibular first and second molars were recorded for each root. Three examiners performed the measurements separately. ANOVA was used to compare the different roots. Bonferroni's post-hoc test was used for pair-wise comparisons when ANOVA was significant. The significance level was set at p ≤ 0.05. The findings displayed a closer proximity of the mandibular second molar apices to the IAC, as compared to the mandibular first molars. The mesial roots were at a shorter distance than the distal ones. Moreover, the mandibular second molars revealed the thickest total bone width including the root. So, it is beneficial for endodontists to be aware of the relation of the mandibular first and second molars to the surrounding cortical bone plates and the IAC before starting either nonsurgical or surgical endodontic treatment.

Assessment of Anterior Loop of Inferior Alveolar Nerve – A Cone Beam Computed Tomography Study

Introduction: The anterior loop (AL) of the inferior alveolar nerve (IAN) and the mental foramen (MF) are important anatomical structures that should be taken into consideration during preoperative planning in the anterior mandibular region. This study aims to assess the prevalence, length, and type of the AL of the IAN in males and females in a South Indian population. Additionally, the distance from the MF to the lower border of the mandible is assessed. Materials and Methods: A total of 115 cone-beam computed tomography (CBCT) scans of 230 sides of mandibles were taken using a Carestream Select CS9300 CBCT machine (Carestream Dental LLC, Atlanta, USA). The scans were selected from archives and divided into three different age groups (<40, 41–60, >61 years). The scans were analyzed to detect the canal of the AL of the inferior alveolar nerve canal (IANC). The IANC, along with the AL canal and part of the incisive nerve canal, was traced using the CS 9300 software. The length of the mandibular nerve was measured for each patient in cross-sectional and panoramic views. Results: The AL was present in 92.6% of the 115 participants. Overall anterior loop length ranged between 0.9 and 15.2 mm. The mean length of AL in panoramic view on the right side was 3.284 ± 2.314 mm and it was 3.015 ± 2151 mm on the left side. Y-shaped AL was more predominant when compared to T-shaped AL in the sample. Conclusion: The prevalence of AL was relatively higher in subjects ranging from 41 to 60 years with a slight increase in female predominance.

Do two- and three-dimensional imaging show the same risk of nerve injury during extraction of mandibular third molars depending on their angulations and distances to the inferior alveolar canal? – A retrospective clinical study over 8 years

ObjectivesInjury of the inferior alveolar canal (IAC) is a common complication during mandibular third molar (MTM) surgery. The aim of this study was to compare the MTM risk assessment using orthopantomography (OPG) and cone beam computed tomography (CBCT) images showing different MTM angulations and distances to the IAC. Materials and methodsThis retrospective study investigated 388 lower third molars of 259 patients radiologically over eight years using OPG and CBCT. Measurement and categorisation of MTM position showed four different types of angulations: vertical (type 1), mesioangular (type 2), horizontal (type 3) and distoangular (type 4). The shortest distance from the MTM and the IAC was measured and categorized after a risk classification (class 1–3) for injury of the IAC. ResultsHigh risk (class 1) was detected in 38.4%, moderate risk (class 2) in 21.9%, and low risk (class 3) in 36.1% using OPG data. In CBCT, high risk (class 1) was found in 11.6%, moderate risk (class 2) in 5.7%, and low risk (class 3) was fount in 78.6%. The same risk classification for OPG and CBCT was present in 25.1% of cases. The most common angulation was type 1 in 49.7%, followed by type 2 in 40.5%, 5.2% in type 3, and 4.4% in type 4. ConclusionPreoperative CBCTs are essential for risk evaluation and treatment planning in MTM surgery due to differences in OPG and CBCT data regarding nerve injury risk.

Inferior alveolar nerve canal segmentation by local features based neural network model

The detection of Inferior Alveolar Nerve Canal (IAC) plays major and crucial role in dental surgical procedures to avoid damage to IAC during the course of treatment. Exact visualization and detection of IAC is necessary for precise surgery planning to prevent IAC damage. The proposed method comprises of three stages namely, novel edge enhancement, candidate classification and candidate pixel clustering to detect the IAC. For better visualization of IAC, initially the edges of dental OPG images are enhanced using a novel structural filter. Candidate regions are selected from the enhanced image by the proposed Multi Hidden Layer Extreme Learning Machine Artificial Neural Network (MELMANN) model driven by combined regional features such as Histogram of Gradients (HOG), Local Binary Pattern (LBP) and Gray Level Co-occurrence Matrix (GLCM). Consequently the candidate region pixels are clustered by a Self-Organising Map-based Neural Network (SOM - NNC) along with active contour method to detect the IAC completely. Experimental results show that this method effectively delineated the IAC with the Dice coefficient of 0.854 ± 0.05.Therefore, the proposed method has high potential in clearly visualizing IAC to avoid neurological sensory disorders in oral and maxillofacial surgery and implantology and it provides better prediagnostic approach to the surgeons.

Relationship Between Lower Third Molars and Mandibular Alveolar Canal through Cone Beam CT Scans

Background: Third molar extractions are considered one of the most common procedures in oral surgery. Well-known complications of these procedures are lesions to the inferior alveolar nerve because of its proximity to the roots of third molars. Hence, it is important to making an adequate assessment of this relationship to avoid complications. Purpose: To determine the relationship between the inferior alveolar canal (IAC) retained lower third molars, and that relationship with angulation, class and type of lower third molars through cone-beam computed tomographies. Methods: A descriptive and transversal study was conducted with 73 tomographies to 113 lower third molars that were analyzed in the axial, occlusal, and sagittal planes (p = 0.05). Results: 54 % of third molars were in contact with the IAC and more frequently in its lower location (45.9 %) (p = 0.000). Proximity relationships were more common on the left side with a vertical angulation (40.6 %), type A (37.5 %), and class II (75 %) (p = 0.015). On the right side, a mesioangular angulation (34.5 %), type A (48.3 %) (p = 0.004), and class II (58.6 %) (p = 0.000) were the most common. Conclusion: A close proximity relationship of the IAC with the lower third molars was found using cone beam computed tomography, and it is recommended to conduct a careful diagnosis before a surgical procedure.

Comparison of Digital OPG and CBCT in Assessment of Risk Factors Associated with Inferior Nerve Injury during Mandibular Third Molar Surgery.

Background: Pre-operative radiographic assessment of the anatomical relationship between the roots of the mandibular third molar and the inferior alveolar nerve (IAN) is a must to minimize the risk of IAN injury during surgery. Objectives: To compare the radiographic signs of digital orthopantomogram (OPG) and cone-beam computed tomography (CBCT). An additional objective was to assess the cortex status between the mandibular canal and third molar on CBCT images in relation to the demographic characteristics, region (right or left side), and angulation of mandibular molar. Methodology: In this retrospective study, a total of 350 impacted mandibular third molars with a close relationship between the inferior alveolar canal (IAC) and impacted mandibular third molars on digital OPG were further referred for CBCT imaging for assessment of the position of the mandibular canal. The study was conducted between August 2018 and February 2020. Digital OPGs were evaluated for radiographic signs like interruption of the mandibular canal wall, darkening of the roots, diversion of the mandibular canal, and narrowing of the mandibular canal. The age and sex of patients, site of impacted third molar, Winter’s classification of mandibular third molar, position of IAC relative to impacted molar, and the radiographic markers of OPG were assessed for cortical integrity using CBCT. Chi square testing was applied to study the values of difference and binomial logistic regression was done to assess the factors associated with cortication. Statistical significance was set at p ≤ 0.05. Results: Among 350 patients, 207 (59.1%) were male and 143 (40.9%) were female with a mean age of 36.8 years. The most common OPG sign was interruption of white line, seen in 179 (51.1%) cases. In total, 246 cases (70.3%) showed an absence of canal cortication between the mandibular canal and the impacted third molar on CBCT images. Cortication was observed in all cases with a combination of panoramic signs which was statistically significant (p = 0.047). Cortication was observed in 85 (50.6%) cases where IAC was positioned on the buccal side, 11 (16.9%) in cases of inferiorly positioned IAC, and just 8 (7.6%) for cases of lingually positioned IAC which was statistically significant (p = 0.003). Statistically insignificant (p > 0.05) results were noted for cortex status in CBCT images with regards to the age, sex, site, and angulation of impacted third molars. Conclusion: CBCT imaging is highly recommended for those cases where diversion of the mandibular canal is observed on OPG and when the roots are present between canals.

Variability associated with mandibular ramus area thickness and depth in subjects with different growth patterns, gender, and growth status

The purpose of this study was to quantitatively evaluate the ramus bone parameters (ramus thickness and ramus depth) for miniscrew placement. An additional aim was to compare and contrast the ramus bone parameters in growing and nongrowing male and female subjects with hyperdivergent, normodivergent, hypodivergent facial types.Cone-beam computed tomography scans of 690 subjects were evaluated. They were classified in terms of growth status, gender, and facial type. Ramus thickness was measured as the distance from the outer (buccal) to the inner (lingual) aspects of the mandibular ramus. Ramus depth was measured as the distance from the anterior border of the ramus to the inferior alveolar nerve canal. The measurements for ramus thickness and ramus depth were performed at 3 different levels bilaterally: (1) occlusal plane (OP), (2) 5 mm above the occlusal plane (5OP), and (3) 10 mm above the occlusal plane (10OP).Males showed a significantly higher ramus thickness than females (P <0.05). Ramus thickness decreased significantly (P <0.05) as we moved superior from the level of OP to 5OP and 10OP in all 3 facial types in both females (growing and nongrowing) and males (growing and nongrowing). Growing females and growing males had significantly higher ramus thickness than nongrowing females and nongrowing males, respectively. Ramus depth increased as we moved higher from the OP to 10OP. Hyperdivergent facial type showed a significantly reduced ramus depth compared with hypodivergent and normodivergent facial type in growing and nongrowing males and females at all 3 locations, namely OP, 5OP, and 10OP (P <0.05).Because of adequate ramus depth and ramus thickness, 5OP was considered the optimal insertion site for the placement of miniscrews. Patients with a hyperdivergent facial type showed significantly reduced ramus depth than hypodivergent and normodivergent facial types. Ramus thickness in males was significantly higher than in females in all facial types.

ASSESSMENT OF NEUROSENSORY DISTURBANCES AND RECOVERY FOLLOWING SURGICAL REMOVAL OF IMPACTED MANDIBULAR THIRD MOLAR – A PROSPECTIVE STUDY

Aim: This prospective study aim to determine the incidence and pattern of recovery of IAN and LN decits after surgery while comparing which nerve, site, side, age group and type of impaction was most likely to suffer from neurosensory disturbances and to evaluate the risk factors such as duration of surgery, proximity to inferior alveolar canal, excessive hemorrhage, clinical observation of neurovascular bundle, contributing to these postoperative neurosensory decits. Materials&amp;Methods: This study was conducted on 30 patients who underwent surgical removal of impacted mandibular third molar between 2017-2019 in the Department of Oral and Maxillofacial Surgery, College of Dental Sciences, Davangere. Clinically, all the patients underwent objective evaluation by using pin prick test, two-point discrimination and blunt test. Sensory function was evaluated 1 week, 1, 3 and 6 months post-operatively. The areas that were evaluated are those supplied by IAN and LN. Result: The incidence of NSD in our study was 10%, the IAN 6.7% and LN decit 3.3%. No permanent NSD was observed in this study. Statistically signicant association was found between excessive hemorrhage from the socket and NSD (p=0.009). No signicant association was found between gender, age, side, type, difculty score and duration, observation of neurovascular bundle during surgery and proximity of roots to the inferior alveolar canal with NSD.

Evaluation of the Outcomes of Coronectomy Procedure versus Surgical Extraction of Lower Third Molars Which Have a High Risk for Inferior Alveolar Nerve Injury: A Systematic Review.

Results No study reported permanent inferior alveolar nerve injury (p-IANI) regarding coronectomy; however, transient inferior alveolar nerve injury (t-IANI) was reported in 0–2.20% of successful coronectomy and 0–8% of failed coronectomy. Postextraction t-IANI ranged from 0% to 16.66% while p-IANI from 0% to 3.63%. In 5 studies, root migration occurred in 2% to 85.3% of cases and the distance rate was 2.33–3.43 mm at 6 months postoperatively; then the migration gradually decreased and stopped at 12 months. Conclusion This systematic review revealed that coronectomy is an efficient alternative for the management of impacted 3rd M with a high risk of IANI. Patients who got antibiotics postcoronectomy procedures had lower infection rates than those who did not receive antibiotic therapy. We recommend further research on coronectomy with longer follow-up periods to assess the retained roots' long-term outcomes and to assess the effect of antibiotics administration on postcoronectomy infection rate. This systematic review is registered under number CRD42020198394.

Maxillofacial Radiology 194

CBCT imaging and analysis was performed. Observe unilateral expansion by the distending soft tissue outline illustrated through 3D rendering (Figure 2). Sagittal oblique (Figure 3) and axial (Figure 4) slices depict a round heterogenous predominantly high-density lesion with an encompassing thin uniform less dense peripheral band. Irregular root resorption, displacement of the inferior alveolar nerve canal, buccal-lingual cortical expansion, thinning, and interruption was apparent. Irregular thickening at the inferior border and surrounding osteosclerosis were noted. A macroscopic view (Figure 5), photomicrograph (Figure 6), and conventional radiograph (Figure 7) of vertically sectioned surgical specimens of similar lesions. Note the intimate relationship with the tooth roots.

Estimation of Sexual Dimorphism of the Mandible in Coastal Karnataka and Kerala Populations using Cone Beam Computed Tomography

Abstract Objective The mandible has been used for sex determination and forensic identification due to its unique anatomy and morphology. Every part of the mandible is unique, including the shape and size of the temperomandibular joint, the ramus, the body and the symphysis region, and the inferior alveolar canal. In addition, the position and placement of the teeth within their sockets are unique for every individual. Sample Population A study was conducted on 20 males and females to estimate sexual dimorphism using anthropometric measurements obtained by cone beam computed tomography images of the mandible of Karnataka and Kerala populations. Materials and Methods The mean, standard deviation, and standard error along with the confidence interval of different measurements were documented. Various measurements between the sexes were compared using Student's t-test. Association between categorical variables was analyzed using the Chi-square test. A p-value &lt; 0.05 was considered to be statistically significant. Data were analyzed using statistical SPSS software. Results The p-value of mRBr L, GA L, and GA R among females was significantly higher in the Karnataka population when compared with that in the Kerala population. The Karnataka State population showed significantly higher values of RL R, BiGBr, and BiCBr among males, and the p-value of the Kerala population for GGL L and GGL R was significant and higher among the males. Conclusion The data derived from the above study suggest that the mandibular anthropometric measurements used may be applied for forensic sex estimation.

Inferior alveolar canal segmentation based on cone-beam computed tomography.

The shape and position of the inferior alveolar canal (IAC) are analyzed to effectively reduce the risk of iatrogenic injury based on cone-beam computer tomography (CBCT). To assist dental clinicians to make better use of the IAC information, we propose an IAC segmentation method based on CBCT images. In this paper, CBCT images are first preprocessed by the Hounsfield unit values clipping and gray normalization. Secondly, based on the multi-plane reconstruction (MPR) and curved surface reconstruction, the curved MPR image sets are generated by the smooth dental arch curve with a sampling distance of 1.00pixels. Then, the K-means clustering algorithm is used to cluster the texture parameters of the gray level-gradient co-occurrence matrix enhanced by the gradient directions to improve the image contrast of the IAC. Finally, the IAC edges are roughly segmented by the 2D line-tracking method, and smoothed by the fourth-order polynomial to obtain the final segmentation result. Twenty-one real clinical dental CBCT datasets were used to test the proposed method. The manual segmentation results of two specialized dental clinicians were used as quantitative evaluation criteria. The dice similarity index (DSI), average symmetric surface distance (ASSD), and mean curve distance (MCD) of the left IAC are 0.93 (SD=0.01), 0.16mm (SD=0.05mm), and 1.59mm (SD=0.25mm), respectively; the DSI, ASSD, and MCD of the right IAC are 0.93 (SD=0.02), 0.16mm (SD=0.05mm), and 1.60mm (SD=0.30mm), respectively. The proposed method provides an effective image enhancement and segmentation solution to analyze the shape and position of the IAC. Experimental results show that the relationships between the IAC and other structures can be accurately reflected in the panoramic images without superimposition and geometric distortion, and the smooth edges of the IAC can be segmented.

Management of Covid Associated Mucormycosis of Mandible: A Mountain Beneath a Molehill-A Lesson Learnt.

The opportunistic infection of post-Covid associated mucormycosis has been reported globally; however, it has reached alarming proportions in India. Mucormycosis of the mandibular region is rare, and only a few cases have been reported to date. Covid associated mucormycosis has not been reported in the literature before, and we are the first to report them. We report two patients who presented with tooth loosening with pus discharge a few weeks following recovery from Covid infection. After tooth extraction adjacent necrotic bony specimen was sent for calcofluor potassium hydroxide mount, which was found positive for broad pauciseptate hyphae. Although CT scan imaging demonstrated the involvement of a mandible segment, we found a much more extensive involvement in both cases during resection. There was intramedullary spread of the mucormycosis throughout the inferior alveolar canal, with pus discharge and foul odor. The management of covid associated mandibular mucormycosis consists of surgical debridement with antifungal therapy and control of the underlying disease. It became challenging because the radiological extent of the disease was different from the definite clinical extension of the lesion found during surgery. The authors recommend surgeons adopt a flexible approach during surgery to plan resection depending on the clinical judgment and not rely entirely on CT scans. And the reconstruction of the mandible will follow as per the extent of excision.

1678 A Rare Example of a Simple Bone Cyst of The Ascending Ramus in A Paediatric Patient

Abstract A simple bone cyst is described as an intra-osseous pseudocyst, devoid of an epithelial lining and either empty of filled with serous or sanguineous fluid. This case presents a rare example of a simple bone cyst of the ascending ramus of the mandible in a paediatric patient. Studies have shown that less than 5% of simple bone cysts of the jaw bones are located within the mandibular ramus, with the most common site being the premolar-molar region (75%). The 14-year-old female was referred by her orthodontist to the local Oral and Maxillofacial department, for an incidental finding on her pre-orthodontic OPT of a radiolucency in the left ascending ramus. Her medical history was clear, she was asymptomatic and had no sensory deficit. A CT scan demonstrated a 22mm multilocular radiolucency centred on the left ascending ramus, extending superiorly up to the base of the coronoid process and condylar neck. Inferiorly, the radiolucency abutted but did not involve the unerupted third molar. The scan highlighted thinning of the buccal and lingual cortices putting the patient at risk of pathological fracture. The inferior alveolar nerve canal passed through the lingual aspect of the radiolucency. The patient underwent exploration of the left mandible which revealed an empty bony cavity, with no cystic lining or contents. The definitive diagnosis of a simple bone cyst was established. She experienced satisfactory healing by her review appointment 4 weeks post-surgery. Combined radiographic and clinical assessment is important in the diagnosis of simple bone cysts.